Example embodiments relate to a semiconductor device, and more particularly, to an analog-digital converter (ADC) configured to remove an offset component of an amplifier, and an image processing device including the ADC.
General image sensors are roughly classified into charge coupled device (CCD) image sensors and CMOS image sensors (CISs). Compared with the CCD image sensors, the CISs are relatively economical because they can be manufactured using general CMOS technology, and are advantageous because they can be integrated with an analog/digital signal processing circuit with relative ease.
In addition, the CISs can be designed to operate with low power and low voltage, and are widely used in portable apparatuses such as mobile phones, smart phones, or digital cameras requiring low power consumption. A pixel array of a CIS includes a plurality of pixels arranged in a two-dimensional matrix. Each of the pixels may generate an image signal from an optical signal. In detail, each of the pixels integrates photocharges corresponding to the amount of light incident using a photodiode and generates an analog pixel signal corresponding to the integrated photocharges.
In general, the analog pixel signal output from each of the pixels is converted into a digital signal by an ADC, and the digital signal is image-processed by an image signal processor (ISP). A conventional delta-sigma (ΔΣ) ADC that can be used during analog-digital conversion may convert an analog pixel signal into a digital bitstream by delta-sigma modulation, and obtain the digital signal corresponding to the analog pixel signal from the digital bitstream.